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Biomedical subjects

M Matsuki

Publications and source records attributed to M Matsuki.

At least 109 records · Page 6Linked to original sources
PubMed1983

Adrenocorticotropin-mediated effect of metoclopramide on plasma aldosterone in man.

Five healthy adult men were given metoclopramide (10 and 20 mg) iv and the effects of L-dopa and dexamethasone on metoclopramide-induced increases in plasma aldosterone concentration were determined. Plasma PRL, ACTH, and cortisol levels were also measured and the results reported in a previous study. After an injection of 10 mg metoclopramide, aldosterone levels increased significantly. The aldosterone rise was inhibited by L-dopa, but not by dexamethasone. After injecting 20 mg metoclopramide, aldosterone levels increased significantly vs. both the control and the basal level. The aldosterone increase was not inhibited by L-dopa pretreatment, whereas pretreatment with dexamethasone did suppress it. The data suggest that metoclopramide increased aldosterone secretion through an ACTH-dependent (stress mediated) effect in addition to its antidopaminergic adrenal action, simultaneously. There were no significant differences between the ACTH-dependent and dopamine antagonist-mediated aldosterone increases in either the 10- or 20-mg tests. However, the ACTH-dependent aldosterone increase was statistically greater in the 20-mg test than in the 10-mg test, whereas there was only a slight and not statistically significant difference in the dopamine antagonist-mediated aldosterone increase between the tests. This means that the ACTH-dependent component of the aldosterone secretion is affected by the doubling of the metoclopramide dose, whereas the dopamine antagonist-mediated component is not.

Adrenocorticotropic Hormone↗
PubMed1982

The discrepancy between plasma 11-deoxycortisol and ACTH concentrations in a single dose metyrapone test in normal men.

A single dose methyrapone test (MTP test) was carried out on 6 normal men by administering 1.0 g of metyrapone at 08.00-09.00 h with and without dexamethasone (DXM-MTP test) pre-treatment. Plasma 11-deoxycortisol, pregnenolone, ACTH and cortisol were measured before administration of the drug, and at hourly intervals for 6 h. In the MTP test, 11-deoxycortisol increased significantly at 1 h with a peak at 5 h, whereas significant increases in pregnenolone and ACTH were not seen until 3 h. There was a definite decrease in the cortisol level at 1 h with the lowest level measured at 2 h. Thus, a time discrepancy between plasma 11-deoxycortisol and ACTH concentrations was observed. The increase in 11-deoxycortisol after metyrapone should be divided into two phases: the increase in phase II (after 3 h) is due to the pituitary ACTH reserve, and that in phase I (the first 2 h) is due to some mechanism other than the pituitary ACTH reserve. The increased amount of 11-dexoycortisol in phase II (218.1 nmol) occupied 60.5% of the total increased amount in phases I and II (360.6 nmol). The cortisol/(cortisol + 11-deoxycortisol) ratio reached its lowest point 3 h after metyrapone treatment. This might be due to the initiation of an additional surge in 11-deoxycortisol by the ACTH reserve at 3 h.

17-Hydroxycorticosteroids↗
PubMed1982

Dorsal column stimulation in man: facilitation of primary afferent depolarization.

The effects of cervical epidural dorsal column stimulation on the negative and slow positive waves of the spinal cord potentials recorded from the posterior epidural space at the lumbar enlargement, in response to intense stimulation of the tibial nerve in five neurologically normal subjects during neuroleptanesthesia were studied. Single pulses applied to the cervical dorsal cord near the midline produced slow positive potentials preceded by negative waves in the dorsal spinal cord at the level of the lumbar enlargement. The negative wave, believed to represent synchronized activities of interneurons, was inhibited up to 100 to 120 msec by conditioning dorsal column stimulation. The slow positive wave, though to represent primary afferent depolarization, was facilitated for more than 100 msec with transient inhibitor for 10 to 40 msec. The results suggest that the pain-alleviating effect of dorsal column stimulation in man may be at least partly due to orthodromic and/or antidromic activation of descending inhibitory pathways which inhibit the responsible cells and facilitate primary afferent depolarization.

Adolescent↗
PubMed1981

Gel chromatographic separation of human C-peptide and proinsulin.

The immunoreactivity of circulating C-peptide is separated into two main peaks on a Bio-Gel column; the faster peak should not be proinsulin but an associated C-peptide without a covalent bond. Proinsulin is in fact eluted in the fraction prior to the faster eluting peak of C-peptide immunoreactivity with 1 M acetic acid as the eluting buffer. Therefore the use of gel chromatography to study C-peptide and proinsulin needs to be carefully re-evaluated, although the method has been established as one of the standard methods.

C-Peptide↗